Characteristics of the lipid and fatty acid compositions of the Humboldt squid, Dosidicus gigas: The trophic relationship between the squid and its prey

Abstract

The lipids and fatty acids of the Humboldt squid (Dosidicus gigas) were examined to assess its lipid physiology and the relationship between the squid and its prey. Similar to highly migratory fishes, D. gigas has high levels of 22:6n‐3 (DHA) in its TAGs (21.9–29.0% for mantles and 21.8–23.9% for arms), different from stomach content lipids (1.9–16.5%), which fluctuated or were at very low levels in some samples. The major PUFA in the tissue (mantle, arm, integument, and gonad) phospholipids were 20:5n‐3 (icosapentaenoic acid, EPA), and DHA. Markedly high levels of both EPA and DHA with noticeable levels of 20:4n‐6 (arachidonic acid; ARA) were observed in phosphatidylethanolamine (17.2–28.8% for EPA, 8.8–22.6% for DHA, and 2.4–11.8% for ARA), while DHA was found as a major component in phosphatidylcholine (30.6–47.8% for DHA). These findings imply a concentration of these PUFA from the storage lipids in the tissues of D. gigas, and that the squid actively concentrates EPA and in particular DHA as a top predator, similar to highly migratory fishes. D. gigas is a healthful marine food containing high levels of EPA and DHA with noticeable levels of ARA.